AP Stats Project 1 Task 1

Individuals

- an object/ the "thing" being described in a data set

- depending on type of study, individuals can be observational or experimental units

Variables

-attributes of individuals that take different values for different individuals

Data Set

-a collection of data (set of multiple datum)

Categorical Variable

- a variable that assigns labels placing each individual into a category/group

- ex: color, age, group, graduating class

Quantitative variable (blanket term)

- a variable that takes number values that are quantities

Discreet Variable

- quantitative variable that takes on a fixed set of values that have gaps in-between

- ex: shoe size, age, etc.

Continuous Variable

- quantitative variable that takes on any value in an interval; includes in-between values

- ex: height, weight, test scores

Distribution

- something that tells us what values a variable takes and how often it takes those values

Frequency Table

-a table that displays the COUNT/FREQUENCY of observations in each category or interval

Relative Frequency Table

- a table that displays the PROPORTION/PERCENTAGE of observations in each category or interval

Bar Chart

- displays distribution of a categorical variable w/ heights of bars showing frequency/relative frequency for each values

-spaces between bars; used for categorical variables

Pie Chart

- shows the distribution of a categorical variable as a "pie" whose slices are sized by the counts/percentages for the categories

- must include all categories; used for categorical variables

Histogram

- shows each interval of values as a bar, heights of bars show frequencies/relative frequencies of values in each interval

- bars don't have spaces b/t; used for quantitative variables

Stemplot

- shows each value separated into 2 parts:

a) stem: consists of all but the final digit, ordered from lowest to highest and arranged in a vertical column

b) leaf: the final digit, arranged in increasing order from each stem

Split Stemplot

- contains 2 rows for each stem w/ leaves from 0-4 in the first copy & leaves from 5-9 in the second copy

Side-by-side stemplot

- Shows distribution of two variables with common stems

Shape terms

- Symmetric: right and left sides are approximately the same

- Skewed left: tail of data on L, peak at R

- Skewed right: tail of data on R, peak on L

- Unimodal/Bimodal: having 1 or 2 peaks/modes

- Uniform: relative frequency of everything is approximately the same (equally likely)

Unusual Features

- Outliers: data that falls outside the overall pattern of a distribution

- Gaps: spaces between data

- Clusters: data grouped together

Center terms (median/mode)

- Mean: the "average" of the data; add all data together then divide by amount of data

- Median: the "middle" of the data; count how many total values you have and find the midpoint

Spread/Variability Terms

- Range: difference between maximum and minimum values

- IQR: difference between Q3 & Q1

- Standard Deviation: typical distance of the values from the mean

Boxplot/ 5 number summary

- the five number summary consists of....

- minimum

- Q1

- Q2/median

- Q3

- maximum